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Adobe’s PDF format allows you to combine text and images into portable document files which are easy to share with employees, print or store for later use. As the creator of a PDF file, you can dictate the level of protection placed on the document, restricting its manipulation or even preventing unauthorized users from opening the file. Understanding the different layers of encryption PDF offers will help you choose the security best suited to your project.

Standard Protection

The standard level of protection for a PDF allows users to read the document, but not to make changes to it. This level of protection is suitable for promotional brochures, for instance, where you might wish to spread the documents publicly, but you want to ensure the content remains true to your intent. Placing a password on a PDF allows you to set the security level yourself, allowing certain actions by the end-user while restricting others.

Password Protection

The level of restriction you can place on an encrypted PDF depends entirely on what you want users to be able to do with it. For secret documents, you can require that a user must enter a password before he can view the file at all, or you could restrict his ability to print or copy text from the document. You can designate certain areas of the PDF as unprotected, allowing users to fill in information fields and save the completed document for later use. You can define these levels of control through the Document Properties option when creating your PDF file.

Certificate Security

While password security is suitable for internal documents, sharing PDFs outside your organization may bring up security issues. Sharing a password via email could leave it open to interception by third parties. To combat this, you can use certificate security to protect your documents. This method involves public key encryption, allowing users to guarantee the identity of the document’s creator, and ensuring that only the specific recipients can access the file. You should always use a third-party security certificate from a trusted source such as Verisign or Thawte to secure these documents, as they can replace lost or deleted certificates if needed. If you create your own certificate for this method, deleting the file will permanently lock any PDFs created with that certificate.

Consideration

While passwords can help keep outsiders out of your PDF files, you should always remember that the strength of the password contributes greatly to the security of the file. Short passwords, or those that third parties could find in a dictionary, can easily fall to brute-force attacks. In addition, users may be able to get around copying or printing restrictions by using files that capture images of each PDF page and use optical character recognition to re-create the text.

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About the Author

Milton Kazmeyer has worked in the insurance, financial and manufacturing fields and also served as a federal contractor. He began his writing career in 2007 and now works full-time as a writer and transcriptionist. His primary fields of expertise include computers, astronomy, alternative energy sources and the environment.